There are several programmable thermostats now available in the market. Typically, to operate these thermostats, a user individually selects a plurality of times and individually assigns a desired temperature to each time. This information is stored in a memory of the thermostat. The thermostat then controls the heating and/or cooling system according to the programmed times and temperatures in a well known manner. An example of one program is shown in Table 1.
TABLE 1 ______________________________________ Prog. Time Temperature Remarks ______________________________________ 1 6:00 AM 68 F. Wake up 2 8:00 AM 60 F. No one at home 3 3:30 PM 69 F. Children return home 4 11:00 PM 63 F. Sleep ______________________________________
As can be seen from Table 1, four times and temperatures are entered. These entries are designated by program numbers (1-4). Each of these programs numbers has associated with it a time and a temperature. The remarks are provided as an explanatory device for this example. In this example, at 6:00 AM the temperature is set at 68 F. This corresponds to a time when people would normally wake up in the house. By 8:00 AM everyone leaves the house so the temperature can be lowered. In this case, at 8:00 AM the temperature setting is lowered to 60 F. At 3:30 PM the children return to home so it is desirable to raise the temperature to 69 F. Finally at 11:00 PM everyone goes to sleep so the temperature is lowered, in this case, to 63 F. It is to be noted that this is just one example of a program set containing a plurality of times and temperatures which is used to vary the temperature throughout the day based on the schedule of individuals in the house or other environment which the thermostat is to control. It is to be understood that other programs may be desirable for other users. More or less than four times and temperatures may also be desired.
In many of these thermostats, a default program is provided. The default program is a program which is automatically loaded into the memory during power-up of the thermostat. In essence, it is part of an initialization of the thermostat. The thermostat controls the heating and cooling system according to the default program parameters if the user does not insert his or her own program at the time of installation or after power-up. An example of a typical default program is shown in Table 2.
TABLE 2 ______________________________________ Prog. Time Temperature ______________________________________ 1 0.00 68 F. 2 0.00 68 F. 3 0.00 68 F. 4 0.00 68 F. ______________________________________
In this case, the four times and temperatures are the same for each of the program numbers. Since there is no time distinction made, the thermostat will always be set at 68 F. until a user actually programs different times and temperature information. Therefore, the default program typically remains operable until the user separately programs time and temperature information as desired, for example, as shown in Table 1.
In other cases, the thermostat may have a default program similar to the one shown in Table 1, with a plurality of different times and corresponding plurality of temperatures. In this case, as soon as the unit is powered-up, the thermostat is set according to this default program. The user then alters these settings by individually inserting new times and temperatures as desired. Usually "Hours", "Min" and "Temp" and arrow up/down keys (or similar keys) are used to alter the programs in a program mode in a well known manner. Since the default program has a program set with several times and temperatures which are pre-programmed, these devices are sometimes referred to as "pre-programmed" thermostats. One patent which describes this type of "pre-programmed" thermostat is U.S. Pat. No. 4,308,991. In this patent, the inventors describe the "pre-programmed" concept discussed above, and a method to access those programs and change them to the desired settings. However, various drawbacks exist with the foregoing thermostats.
One problem with the prior art is that since only one pre-programmed program exists, users must individually select and program their own times and temperature to program their thermostat according to their own desired times and temperatures. This is sometimes confusing for some and overly complicated for others. What is needed is a simpler mechanism to enable users to customize or "program" their thermostats.